Uncontrolled cell proliferation is a characteristic of a number of disease states. Such growth is observed, for example, in benign and malignant tumors. Generally, drugs used to treat cellular abnormalities characterized by uncontrolled cell growth target important biochemical steps or processes that are part of the cell growth cycle.
However, such drugs lack selectivity and affect both healthy and diseased cells. For example, numerous drugs currently used for treatment of hyperproliferative diseases are hepatotoxic above a threshold concentration (Saba). Certain antitumor drugs which inhibit growth of highly replicating cells may adversely inhibit the growth of cells in the bone marrow which also contains highly replicating cells (Salmon).
It would therefore be advantageous to have available a method for controlled, prolonged release of a drug in the bloodstream at a selected tumor site.